Laboratory pump for drawing up fluids in a pipette



Nov. 22, 1955 G. F. PERSSON ET AL 2,724,275l

LABORATORY PUMP FOR DRAWING UP FLUIDS IN A PIPETTE Filed March 21, 19523 Sheets-Sheet 1 INWFNTORS- Qusrnf I 3: [1,, 104% PIP-110N- y 6 wm/ Nov.22, 1955 sso Er AL 2,724,275

LABORATORY PUMP FOR DRAWING UP FLUIDS IN A PIPETTE Filed March 21, 19523 Sheets-Sheet 2 III I [Ll/I g'wmv Fume P6258014 9 A4724 fixrare Pa/wavy Maw 27M Nov. 22, 1955 G. F. PERSSON ET AL 2,724,275

LABORATORY PUMP FOR DRAWING UP FLUIDS IN A PIPETTE 3 Sheets-Sheet 3Filed March 21, 1952 Kim. VIKTOR P516580,

United States PatentOfifice LABORATORY PUMP FOR DRAWING UP FLUIDS in APIPETTE Gustav Folke Persson, Norrkoping, and Karl Viktor Persson,Sundasen, Sweden Application March 21, 1952, Serial No. 277,802 8Claims. (Cl. 73-425.6)

In laboratory work it occurs often that fluids are to be measured ordrawn up. Drawing up is usually efiected by means of a pipette, which isdipped into the fluid, where- .upon air is removed through the other endof the pipette, with the result that the fluid rises in the pipette.Suction is ettected with the mouth or by means of a special suctiondevice, suchas a rubber ball or a pump. To draw up the fluid with themouth is convenient, to be sure, but

it is often attended with great disadvantage. When drawingup a fluidwith the mouth, there is always a risk of mark on the pipette and toclose the upper end of the pipette with the finger and than let in somuch air that fluid runs out to the volume desired. The adjustment ofthe volume is, attended with certain difliculties, because itisdifficult to adjust the volume of air with the finger. In the case ofpipette balls and pumps of an older type, the, suction and emptyingspeed of the air current, and consequently of the fluid, cannot beregulated satisfactorily, and therefore it is difficult to measure anydesired volume. to a great extent have to be used, and that noconvenient device is available for attaching the pipette or the suctiontube to the pump or ball. e

n This invention refers to a pump for this purpose, consisting of a pumpbody provided with a suction device, a

device for attaching pipettes, and a suction channel and connectingchannels between pipette attachingdevice and the suction device, inaddition to which there is arranged in the pump body a valve intendedfor closing or opening the connection between the pipette and thesuction device and comprising a valve body at right angles to thepipette and/or a valve control rod, through or around which a channel isarranged, by means of which the suction device can be connected with orshut off from the outside air.

The invention is characterized in that the attaching device for pipettesincludes a tightening device suitable to tighten against all normallyavailable pipette diameters, and suitably consisting of a stopper ofelastic plastic ma- ,terial placed into a cylindrical recess in theunderside of "the pump body, provided with a cylindrical recess with adiameter equal to or larger than the largest pipette diameter available,which recess merges into a funnel-shaped bottom, into which opens acylindrical channel connected with the suction channel, having asmallerdiameter than the smallest available pipette diameter.

a The stopper may, moreover, be attached to the-pump body' by means ofan annular ridge, extending into'and t 'i ghte n ing against acorresponding recess in thepump I body. The attaching device forpipettes comprisesalso preferably two jaws covered with elastic plasticmaterial,

advantage is the fact that it is difficult to see the fluid I level whendrawing same up, and therefore it is necessary, when using the pipette,to draw the fluid up above the Other disadvantages are that both handsfittedwith' a plug 34 pointing centrally inwards.

Patented Nov. 22 1$55 which are arranged to swing on two axles fitted inthe pump body and which are pressed against each other by a spring, oneof the jaws being rigidly connected to a control arm suitable to beoperated by one finger of the hand holding the pump. The covering ofelastic plastic material is preferably provided with a V-shaped groove,widening while the bottom angle remains unchanged.

The invention is illustrated by drawings attached hereto, in whichi Fig.1 shows a type of design ofa purnp according to this invention, invertical section;

Fig. 2 shows a difierent type of design in vertical section; and

Fig. 3 shows the same in sideview, partly in section showing the controlmember of the jaws.

Fig. 4 shows another type of design in vertical section;

Fig. 5 shows said last device in a vertical section at right angle toFig. 4; and

Fig. 6 shows the same device in a side view corresponding to the view ofFig. 4, partly in section.

In the'following, the types of design shown will be described in detail,with reference to the drawings, when further characteristic features andadvantages will become apparent.

In a pump body 2 a cylindrical recess 26 is made in its underside. Thisrecess is provided with an annular groove 30, arranged near its opening.In the recess 26 is placed a nipple 4 of elastic plastic material, whichon its outside is provided with a corresponding ridge extending into andtightening against groove 30. The nipple 4 is provided with cylindricalrecess 27 merging into a funnel-shaped bottom 28. From its top a channel29 leads to the bottom in the recess 26. The diameter of recess 27 isequal in size or larger than the largest pipette diameteravailable, andthe diameter of channel 29 is smaller than the smallest availablepipette diameter.

arrangement.

Fig. 1 shows a valve arrangement in a valve sleeve 11, which is threadedinto a recess 37 in pump body 2, at right angles to channel 5, andprojects from the pump body. The sleeve 11 is open at the outer-end,and-is This plug 34 is at its base fitted with an annular groove,suitable to hold a flat, annular elastic packing 7,*tightened betweenthebottom of sleeve 11 and a shoulder 36 in recess 37. In plug 34 there isa central hole. Sleeve 11 is at its inward end provided with an annular,external shoulder 35 so that an annular channel is obtained betweensleeve 11 and recess 37, to which is arranged a crosswise extendingchannel 33 from the interior of sleeve 11 as well as a channel 16 fromsuction device 1. A control rod 13 is provided with an exterior part-'with the same'external diameter as sleeve 11, and an internal rangedthat its cylindrical part provides good packing against the central holein plug 34. Needle valve 38 is at its free end provided with acylindrical extension, to

which is attached an elastic, hood-shaped packing'6farranged to tightenagainst packing 7. Over the wider outside part of control rod 13 and theprojecting part of "sleeve 11 is placed a rubber hose 12, whichtightens. the

annular channel between these me against the" outside air. Betweencontrol rod 13 and the bottom of sleeve 11 is arranged a pressure spring9, which pressescontrol rod ware. The control rod 13 is immediatelyinside its outer partp'rovi'ded with a cross-channel "41, sothat freeconnection is obtained between the outside air and suction device 1. V gH nitiigt a different arrangement ofthe valve is shown. tnpu'mpyb" I V lrecessfi facing the suction a es s; r'r'a'h'ged, in the bottom erw-hich'channe1'-'5 ends. Qlnrecessc t an lastic plastic stopperzs is.arranged,'"for instance in-the shape of a ball with"th'e same diameteras'thefltor'mer, so that' it" tightens against its wallscontrol rod 13is arranged 'axia'lly movable in a guide sleeve 11, which is placed in arecess arranged at right angles. to recess 24in pump body 2 andextending toward same "without reaching it, ari'd from 'the' bottom ofwhich a recess 39 with a. smaller diameter continues to reces's'24. Thecontrol mars is providedwith an interior .part .with..a.-smallerdiameter fitting into recess 39, and with a central 'hole14 extendinginto' its interior with a blind .end. It is also provided withtransverse hole 3'3 nearthe base of its-interior part, by which a freeconnection is obtained between hole '14 and the annular channel. 8,which .is provided between 'this interior part and sleeve 11. A channel16 is arranged fromfthis annular-channel to the suction devicefl',by;which' same gets direct connection with the outside-air through hole14. Overcohtr olrod 13 and the part of sleeve 11-projecting from pumpbody 2 is arranged a rubber hose 12, which I tightens againstboth'and at.the same time holds "them The control rod 13 .is so arranged. in pumpbodyl2 thatits point-when pressed inward meets ball 25 {frornithe side,deforming it so that it no longer tightens against the walls 'of recess"24.

Qnxpump body 2, twoaxles 17 are arranged in parallel and-at .rightanglestofia plane through the centrelines of control rod.13 and recess 26, onwhich twojaws 18 'and19are arranged to swing, with mutually compulsorymotion. bymeans of meshing teeth 31, and covered with .a' layer-32 ofelastic plastic material. These covering layers are provided with avertical, V-shaped groove each, widening inwardswiththe bottom angleunchanged. The jaws 18, 19 are pressed with covering 32 against eachother byfi hairpin spring 20. One jaw, 19., is extended to -'-'serve as.a bent control arm 15, whichis so shapedthat .ljaws 18, 19 .areseparated, when arm. 15. is forced in- -wa rds againstthe pump body.

yin the pump-body may suitably be arranged an extra channel-23 beginningatgchannel 5..and endingatthe :bottornz-ofsrecess 4,0,whereit is .shapedasa nozzle, to :which is-fattached .a rubbersreceptaclell, which is sosmallitlrat th6I6'1lS.-IO0Hl enough for it in recess. 41). In

ian.envelope-3 outside-recess: 40 a scrfewsis threaded, and by screwingthisinorout, thershape .of rubber receptacle .21ccan-bechanged-in'shapeand volume'as desired.

Wh'emthe laboratory pump is to .be.used,controlarm ispressedinwardagainst the pump body,. to. begin -"with,.-so.thatjaws :18,1-9..are .forced apart and a pipette eis-inserted 'between them andpressed withthe .nozzle against the funnel-shaped bottom 28 in nipple 4,where- .upon the control arm 15 isreleased. The pipette is now :heldbetween jaws18, 19,.and its point is dipped into the'..fluid-.-to;-be:drawn up. .The rubberball 1 is squeezed to-;.-zgethcn,--suitably with thethum'b; hole 14 iscovered with teenager,and the rubber .ball 1 is released, whereupon 'control. rod '13--is;pressed'-in..sothat the valve arrange- -ment openszthe connectionbetween rubber ball. 1. and. the :pipette, by which' airin. thepipette-is drawn from same into the 'rubbenball, andthe'fluid rises in.thepipette. aWhen:thetlatter-sisfilled. to :the mark, control rod 13 isen-by hi r-i l ttl'i'l ouglhsholet lyl, rubber. ball .1 and. :the valvearrange- ;mentwintothe, pipette, 'causingthe. fluid torunsout. If :-onewishes-.to; hasten the running-out of the fluid, hole 14 is closed, andrubber ball 1 is squeezed together, by which overpressureisobtaineddn"the'pipette. I

If it is desired to obtain very exact measuring, this can beaccomplished by filling the pipette to directly above the mark,whereupon screw 22 is screwed in until the fluid coincides exactly withthe mark.

Instead of the two typeswofiidesign of the invention which. have.beendescribed above many others are conceivable without "going beyondthe scope of thisdnvention. The rubber ball, for instance, can bereplaced by a piston pump. Channel 23'and receptacle 21 .can be omitted.Instead of nipple 4 and jaws 18 and 19, a cylindrical .nipple with acylindrical holecan be. used, which is compressed axially 'in acylindrical recess, so that it will expand inwards in the. direction ofthe centre of the hole, by which its diameter is reduced.

According to a simplified design shown in Figs. 4 to 6, the pump body atits top is provided with a recess forming an internal flange as a seatfor a mainly "conical'rubber stopper" 51. The stopper is .held in placeby 'a'sprin'g 49 located in an appropriate recess in the pump' body 2.The stopper closes the communication between"the recesses 26 and-48.

The control rod 13 has mainly the formof a'tube 44 with an internalchannel 141 and guided'into a cylindrical bore 59 in'the pump body2.Theinner end-of the tube .44 is provided with a recess 47 into which anopening4'6 in the tube wall emerges. Onthe outer end of controlfrod"13.and a cylindrical extension 45of the pump body 2 surroundingthe't'ube 44 is forced a'rubber sleeve 12.

When control rod '13 is pushed inward the "stopper'51'"is deformed andrecesses 4 8.and 26 communicate with each other. "If'the. externalopening'of channel is not'closed,

for instance by thethumb, said recesses also communidate with theoutside space via channel 14, opening 46 and recess 47.

The level adjusting means visible in Figs. 5*a'ntl 6 consists of arubber hood inserted in a circular recess '54 at a side of pump body'2which recess communicates withthe recesses 26 and 48 throughtheope'ning 53. The rubber hood 55 is pressed upon by a screw 58threaded into an opening 57in the'pa'rt '56 of the envelope 3. 'Saidenvelope is also provided with a protruding tongue 43 serving as a restwhen the device is gripped into'the hand.

' What we claim is: V

'1." In a pipette charging device, the combinationo ffan elongated bodymember having a suction channel extending longitudinally therethroughwith a pipette engaging orifice/at one end, a bulbular suctionproducingmember carried by said body member and disposed over the otherend of saidv suction channel for establishing a "suction .at the pipetteend of said suction channel, said suction ch'annel'beingfenlarged atoneend and having a smallerldiam- .eter atthe. pipette end thereof, adeformableel'astic'valve -mern b.er' disposed within the portion of saidfsu'ction channel of .enlarged diameter and operating to "closesaidsu'c- .tion channel at the portion thereof of smaller-diameter,

ing centrally therethrough and having a pipette engaging .orifice. atone end, a bulbular suction producing member .oarriedVbysaidbodymember.and..disposed. over the other end of said suction channel. adapted toestablish a suction in';-'said (suction. channeLsaid. suction, channelbeing ."of a lar ger. diameter at said other .end and having 1a;.idiameter formedbyan annular. shoulder.'therein' atllthe .pipe'ttelengaging. endlthereo'f, a deformable elastic vane faller memberdisposed in the portion of said channel of larger diameter andcooperating with said shoulder to close said suction channel, springmeans for maintaining said deformable valve member against the shoulderin said suction channel, and a plunger means extending laterally intothe side of said body member and engaging said elastic valve memberabove said shoulder for deforming and rendering said elastic valvemember inoperative to close said suction channel.

3. In a pipette charging device, the combination of an elongated bodymember having asuction channel extending longitudinally therethrough andhaving a pipette engaging orifice at one end of said suction channel, abulbular suction producing member carried by said body member andcommunicating with said suction channel for establishing a suction insaid suction channel, a deformable elastic stopper mounted within andnormally closing said suction channel, and a plunger type operatingmeans extending laterally into the suction channel of said body memberfor deforming said elastic stopper and opening said suction channel,said plunger means having an internal bore open at its outer end andcommunieating with the interior of said bulbular suction producingmember at its inner end adapted and arranged to be closed by the fingerof an operator when said plunger means is operated to deform saidelastic stopper.

4. In a pipette charging device of the character described, thecombination of an elongated body member having a suction channelextending substantially centrally therethrough, a nipple at the lowerend of said channel against which the end of a pipette is adapted toengage, a bulbular suction producing member secured upon said bodymember and over the other end of said suction channel, a deformableelastic stopper in said suction channel normally operative to preventthe flow of air therethrough, an operating plunger extending laterallyinto said body member for engaging and deforming said elastic stopperand rendering it inoperative to prevent the flow of air through saidsuction channel, and spring means operating to hold said deformableelastic stopper into sealing relation with said suction channel whensaid plunger is released.

5. In a pipette charging device of the character described, thecombination of an elongated body member having a suction channelextending axially therethrough and having an orifice at the lower end ofsaid suction channel against which the end of a pipette is adapted toengage, a bulbular suction producing member carried by said body memberpositioned over the upper end of said suction channel, a deformablestopper disposed in said suction channel for controlling the flow of airtherethrough, an operating plunger extending laterally into said bodymember for laterally deforming said stopper to thereby permit a suctionin the pipette end of said suction channel when said bulbular suctionproducing member is in an operating condition, and means for axiallypositioning said valve means into sealing relation within said suctionchannel.

6. In a pipette charging device, the combination of an elongated bodymember having a suction channel extending therethrough and adapted to beencircled by three fingers when grasped in the hand of an operator, aplunger extending laterally from the side of said member adapted to beoperated by the index finger of an operator, at deformable elastic valvemember mounted within said suction channel adapted and arranged to bedeformed and rendered inoperative to seal said suction channel by inwardmovement of said plunger, a bulbular suction producing member mountedupon and extending over one end of said body member and communicatingwith said suction channel for establishing a suction in said suctionchannel, whereby said bulbular suction producing member may beconveniently depressed by the thumb when said body member is held in thehand, a pair of opposed spring operated clamping members pivotallymounted at the other end of said body member for holding a pipette incooperating relation with the suction channel of said body member, andlever means formed as a part of one of said clamping members operable bythe index finger of the operator for rendering said clamping meansinoperative to hold a pipette.

7. In a pipette charging device, the combination of an elongated bodymember having a suction channel extending longitudinally therethroughand adapted to be grasped in a hand of an operator, a bulbular suctionproducing member mounted upon and extending over one end andcommunicating with the suction channel of said body member andcompressible by the thumb when said body member is held in the hand ofan operator, the suction channel of said body member being formed of twodiameters with a bypass area in the larger diameter thereof, adeformable elastic valve member disposed in said suction channel fornormally closing said suction channel to the passage of airtherethrough, means operating axially of said body member forpositioning said deformable elastic valve member in sealing relationWithin said suction channel, a plunger member extending into said bodymember laterally of said suction channel adapted and arranged to deformsaid elastic valve member and render it inoperative to prevent the flowof air through said suction channel, said plunger means having an opencentral bore extending from its outer end and terminating short of itsinner end where it communicates with the interior of said bulbularmember to provide an air passageway from the atmosphere to the interiorof said suction producing member when said plunger means is released 1by the finger of an operator.

8. In a pipette charging device the combination of an elongated bodymember having a suction channelextending axially therethrough, abulbular suction producing member mounted upon and disposed over one endof said body member and in communicating relation with said suctionchannel, a pair of axles extending laterally of said body memberintermediate the ends and one at each side of said suction channel,pipette clamping jaws pivotally mounted in opposed relation upon saidaxles, said pivotally mounted jaws having extending portions concentricwith said axles forming an interlocking connection therebetween, springmeans for biasing said clamping jaws toward each other when inengagement with a pipette, and a single lever means carried by one ofsaid jaws disposed outwardly of said body member for opening said jawsagainst the bias of said spring means.

References Cited in the file of this patent UNITED STATES PATENTSGermany Nov. 14, 1940

1. IN A PIPETTE CHARGING DEVICE, THE COMBINATION OF AN ELONGATED BODYMEMBER HAVING A SUCTION CHANNEL EXTENDING LONGITUDINALLY THERETHROUGHWITH A PIPETTE ENGAGING ORIFICE AT ONE END, A BULBULAR SUCTION PRODUCINGMEMBER CARRIED BY SAID BODY MEMBER AND DISPOSED OVER THE OTHER END OFSAID SUCTION CHANNEL FOR ESTABLISHING A SUCTION AT THE PIPETTE END OFSAID SUCTION CHANNEL, SAID SUCTION CHANNEL BEING ENLARGED AT ONE END ANDHAVING A SMALLER DIAMETER AT THE PIPETTE END THEREOF, A DEFORMABLEELASTIC VALVE MEMBER DISPOSED WITHIN THE PORTION OF SAID SUCTION CHANNELOF ENLARGED DIAMETER AND OPERATING TO CLOSE SAID SUCTION CHANNEL AT THEPORTION THEREOF OF SMALLER DIAMETER, SPRING MEANS FOR MAINTAINING SAIDDEFORMABLE VALVE MEMBER IN AN OPERATIVE CONDITION WIHTIN SAID CHANNEL,AND A PLUNGER MEANS EXTENDING LATERALLY INTO THE SIDE OF SAID BODYMEMBER FOR DEFORMING AND RENDERING SAID ELASTIC VALVE MEMBER INOPERATIVETO CLOSE SAID SUCTION CHANNEL.